The Core centralizes the care of our own breeding colony and makes a supply of suckling rats that are not affected by transportation from an outside, distant producer continuously available to investigators. The Core also provides for the individual investigators the means by which suckling rats can be fed rat milk or rat milk substitute (RMS) devoid of biologically-active substances (BAS) in a consistent, coordinated, and standardized manner. The Core additionally facilitates the supervision, training and maintenance of quality control for the many surgical procedures needed in this Program Project.